/*
 * Copyright 2010-2012 Susanta Tewari. <freecode4susant@users.sourceforge.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package commons.util;

import java.io.File;

/**
 * @author Susanta Tewari
 */
public class FileUtil {

    /**
     * The extension is defined as the string followed by the last '.' character. The lowercase
     * of this extension is returned.
     *
     * @param f the file to find the extension for
     * @return the extension of the specified file name
     */
    public static String getExtension(File f) {

        String ext = null;
        String s   = f.getName();
        int    i   = s.lastIndexOf('.');

        if ((i > 0) && (i < s.length() - 1)) {
            ext = s.substring(i + 1).toLowerCase();
        }

        return ext;
    }
}
